30m
Telescope System Summary
(September 2007) 
A maximum of four receivers, from the total of eight, can be used simultaneously. The following table summarizes the allowed combinations and some of the most important receiver characteristics. Plots of the receiver characteristics. HERA cannot be combined with other receivers; up to now not all frequencies have been pretuned. Hera has 18 pixels separated by 24". Local contact for HERA: Albrecht Sievers



(GHz) 
(K) 
(GHz) 
(GHz) 
g_im (dB) 


A100 









>20 
1 
B100 









>20 
1 
C150 









1525 

D150 









0817 

A230 









1217 

B230 









1217 

C270 









1020 
2 
D270 
H

241281

150250

4

1

0913 
2


V 




215241 
120340 


~10 
2, 3 
1) Using a special
external LO, frequencies down to 77 GHz can be measured with good sideband rejection.
For frequencies below 77 GHz,
the sideband recection becomes weaker, and the sideband ratio reaches unity
at 72 GHz
2) Noise increasing with frequency
3) 2x(3x3) pixel receiver with a 24" separation of the pixels. Equipped
with a derotator allowing to follow a source in the sky maintaining the same
"footprint".
Bolometer  Beam  Lambda  Pixels  Spacing between Horns  rms after 10 minutes (normal bolometric conditions) with skynoise removal 
MAMBO I  11"  1.2 mm  37  20"  1.5 mJy 
MAMBO II  11"  1.2 mm  117  20"  1.5 mJy 
local contact for bolometers: Stephane Leon
Below you find the most recent values for the forward and beam efficiencies. We have also compiled the value of the efficiencies in the past .
Here you can find the plot with the most recently measured beam efficiencies.
HPBW('')^{
1)} S/T_A*
3) (Jy/K) 86 29 6.0 110 22 6.3 145 17 6.7 170 14.5 7.1 210 12 7.9 235 10.5 8.7 260 9.5 9.5 279 9 10.4
B_eff^{ 2)}
72 (extrapolated)
34
0.79
6.0
77 (extrapolated)
32
0.79
6.0
0.78
0.75
0.69
0.65
0.57
0.52
0.46
0.42
1) The HPBW can be well fit by: HPBW('') = 2460/freq(GHz).
2) The data can be well fit by a Ruze function B_eff = 1.2 epsilon exp[(4pi R sigma/ lambda)^2] with sigma being the rms value of the telescope optics deformations, R the reduction factor for a steep main reflector, epsilon the aperture efficieny of the perfect telescope and lambda the wavelength in mm. The data can be fit by R*sigma = 0.07 and epsilon = 0.69. The aperture efficiency of the 30m telescope can be obtained using eta_a=B_eff*0.79
3) For a Gaussian source and beam size, and a source which is much smaller than the beam, S(Jy)/T_mb(K)=8.18E7*theta(")^2*nu(GHz)^2 (Rohlfs & Wilson, Tools of Radioastronomy (2. ed., Eq. 8.20). Using the approximation in 1) yields for the 30m telescope S/T_mb=4.95 Jy/K. S/T_A* is obtained by multiplying 4.95 J/K with F_eff/B_eff
Receiver 
F_eff 4) 
A100/B100 
0.95 
C150/D150 
0.93 
A230/B230 
0.91 
C270/D270 
0.88 

Resolution 
Bandwidth 
Receiver (width mode) 
Remark 

1 MHz Filterbank 
1 MHz 
4x256
MHz 
A100, B100 (narrow) 
max 4 parts; series parallel or mixed mode possible; using the filterbanks with 1GHz bandwidth excludes the use of the AC or the 100 MHz FB with the same rx. The FB can be shifted in multiples of 32 MHz from the center frequency of the connected rx. 
4 MHz Filterbanks 
4 MHz 
9x1GHz 
either HERA1 or HERA2 (wide), all other SIS receivers (wide) except 3mm 
max 9 parts; use of the 4 MHz FBs excludes the use of the AC or the 100kHz FB on the same receiver. Frequency switching not available. While the channel spacing is 4MHz, the 3dB width is 5.4 MHz and the noise equivalent width is 6.5 MHz 





WILMA  2 MHz  18x930 MHz  HERA (wide) 

VESPA  3.3 kHz1.25 MHz  10512 MHz  all SIS receives incl. HERA
(narrow) 
Up to 18000 channels. In connection with HERA (9 pixels) the following combinations of resolution (kHz) and bandwidth (MHz) are possible: (20/40), (40,80), (80, 160), (320,320), (1250, 640); local contact: G. Paubert 
XPOL  40kHz1.25MHz  120640MHz  A100 and B100 (narrow) 
Spectral line polarimeter which uses VESPA to determine the four Stokes parameters 
Created by R. Mauersberger
, December 17, 1999,
last change Sep. 12, 2007, by RM